Accelerating walkway

ABSTRACT

An accelerated walkway having a moving surface made up of sets of treadboards of variable length which are mounted between lateral traction chains. A drive mechanism is related with the lateral traction chains. Each set of treadboards has a front treadboard and a rear treadboard that are grooved and mutually articulated along an axis perpendicular to the direction of movement. The rear treadboard of each set of treadboards is mounted on the lateral traction chains and on lateral guidance rails. The front treadboard of each set of treadboards rests on and is displaceable over the rear treadboard of a next set of treadboards in the direction of movement by guide elements. Each of the lateral traction chains includes elbowed links and straight links consecutively articulated to each other through their extremities and run between lateral guides that cause the links to swivel between a folded position, in which the length of the chain is reduced, resulting in the partial overlaying of the treadboards, and a maximum extension position, resulting in the positioning of the treadboards in coplanar alignment.

The present invention refers to an accelerated walkway for conveyingpassengers or materials, which provides major improvements in the easeof use, in its requirements for space necessary for implementation andin the simplicity of its mechanisms.

Different systems are already known for obtaining variable speedwalkways intended for conveying passengers or materials, among which canbe mentioned, as the most important, the following:

1. Variable speed walkway consisting of various rubber bands which areturned at constant speed. The rubber bands at the extremities turn at aslower speed, and the rubber band in the centre turns at a higher speed,whereby a slow speed is achieved at the entrance and at the exit.Walkways with such characteristics are described in the patents EP0854108 A-1, EP 0850870 A-1 and EP 00773,182 A-2.

2. Variable speed walkway consisting of telescopic treadboards. In thissolution the variation in speed is achieved by separating some conveyortreadboards from others. The gap that would be produced is covered bysome plates which initially are hidden below the surface of the adjacenttreadboard. A walkway with these characteristics is described in thepatent GB 2264686 A.

3. Variable speed walkway consisting of parallelepipedal treadboardswhich are displaced laterally with respect to each other. The variationin speed is achieved by changing the direction of movement, maintainingthe projection of the velocity constant over the entrance and exitdirection. This walkway has a characteristic S-shape. Walkways withthese characteristics are described in the U.S. Pat. No. 5,571,254 andin the EP 0646538 A2.

4. Variable speed walkway constituted by a set of interconnectedmotor-driven grooved rollers. The rollers are of reduced diameter,achieving in this way that the working surface is approximately flat.The variation in speed is achieved by making some rollers turn fasterthan others. In a variation of this walkway these roller are employedonly in accelerating and retarding portions. The portions of constantspeed are implemented by means of rubber bands similar to thosepresently used for conveying passengers, as is described in the FR2747664 A1.

5. Variable speed walkway consisting of a deformable rubber band. Thisendless band would be capable of elongation in the centre portion and ofwidening for entrance and exit, thereby achieving the variation inspeed, as is described in the EP 0831052 A1.

6. Variable speed walkway consisting of an endless worm of overlappingtreadboards. The variation in speed is achieved by the displacement ofsome treadboards with respect to others, as is described in the GB2025872.

The walkway of the invention is made up of sets of treadboards ofvariable length which are mounted on lateral traction chains, with whichis related a drive mechanism, in a form similar to that of system 6described above.

Compared with these systems the walkway of the invention ischaracterised in that each set of treadboards comprises a front and reartreadboard, slotted and mutually articulated along an axis perpendicularto the direction of movement.

Of the two treadboards that make up each set of treadboards, the reartreadboard is mounted on the lateral traction chains and also on lateralguidance rails. For its part, the front treadboard rests on and can bedisplaced over the rear treadboard corresponding to the set oftreadboards which is situated immediately in front, by means of guideelements.

According to another characteristic of the invention, each of the sidechains is constituted on a basis of links consecutively articulated toeach other through their extremities. The links in the chains can allhave an elbowed shape or include elbowed links and straight links. Inany case one of the straight spans of the elbowed links is articulatedat its extremities with the adjacent links, be they straight or elbowed.

The chains mentioned run between lateral guides that cause the links, bethey straight or elbowed, to swivel between a folded position, in whichthe length of the chain is reduced, resulting in the partial overlayingof the treadboards that form the walkway, and a maximum extensionposition, in which the chain reaches its maximum length and produces thepositioning of the treadboards in coplanar alignment. It is in thisposition of maximum extension that the links can come to be in alignmentwith the span of elbowed links with which they are articulated.

The swivelling of the links takes place in a progressive manner betweenthe centre span of the chains and the outermost spans thereof, whereby avariation in speed is achieved of the displacement on the surfacedefined by the treadboards, this speed being maximum in the centre spanand minimum in the outermost spans. In the outermost span anacceleration and retardation occur in correspondence with the start orthe entrance portion and the end or the exit portion of the chain,respectively.

The walkway is completed with drive equipment or elements for the twochains that carry in traction the treadboards, a supporting frame, twoside balustrades similar to those of conventional constant speedwalkways, handrails, fixed treadboards in the entrance and exit portionsand the electrical and safety components and elements necessary for thecorrect operation of the walkway, all of which have a constitution anddisposition which are known.

In each treadboard assembly, the rear treadboard is fitted on each ofits sides with longitudinal guides, with two rear coaxial rollers thatform part of the lateral traction chains, and with front coaxial rollerswhich can move over the side guidance elements. The front treadboard, ofeach set of treadboards, has for its part on each of the sides, frontcoaxial sliding or rolling elements, which can move over the guides ofthe rear treadboard corresponding to the set of treadboards situatedimmediately in front.

The support of the chains of the side guidance elements is producedthrough the elbowed links, by means of rolling elements with axleperpendicular to the link. These rolling elements shall preferentiallycoincide with articulations between the links of the chain.

The two treadboards of each set of treadboards have complementaryadjacent edges which are coupled to each other in the coplanar positionof these treadboards.

In the centre portion of the walkway, where the chains run in themaximum extension position, the treadboards of the different sets occupycoplanar positions. In the outermost portions, where the chains run inthe position of maximum folding, the rear treadboards of the differentsets run under the front treadboards, these front treadboards being in ahorizontal position, with the adjacent edges coupled to each other. Inany of the positions described, the axle of the rolling or slidingelements of these front treadboards coincides with the line ofintersection of the parallel planes equidistant from the respectivewalking surfaces of the front sub-treadboard and the adjacent rear one.

When the transition occurs between portions of maximum extension andportions of maximum folding of the chain, the overlapping between frontand rear treadboards varies progressively, the front treadboards beingmaintained in a noticeably horizontal position and the rear treadboardsat a slight inclination, in opposition to the direction of movement.

In the entrance and exit portions, the front treadboards of the sets oftreadboards move in a coplanar and aligned manner, the transition withthe fixed surface of the walkway occurring by means of a system ofcombs.

The traction chains can be engaged at their outermost points withauxiliary pinions or chains that maintain the distance between the linksand also facilitate the tilting of the treadboards between theforward-going and backward-going segment of the assembly. At least oneof these auxiliary pinions or chains can be in relation with the drivemechanism.

All the characteristics stated, as well as others proper to theinvention and the operation of the walkway shall be explained below ingreater detail, with the help of the attached drawings, in which anon-restrictive example of embodiment is shown.

In the drawings:

FIG. 1 is a side elevation in schematic form of an accelerated walkwayconstituted in accordance with the invention.

FIG. 2 is a side view in schematic form of the exit portion of thewalkway of FIG. 1, on a larger scale.

FIG. 3 is a side view in schematic form of the entrance portion of theaccelerated walkway of FIG. 1, on a larger scale.

FIG. 4 is a side view in schematic form of the maximum speed portion ofthe accelerated walkway, on a larger scale.

FIG. 5 is a side view in perspective of a span of the traction chain, inthe portion of maximum speed.

FIG. 6 is a side view in perspective of a span of the chain, in theportion of minimum speed.

FIG. 7 shows in perspective a series of treadboards and adjacent chainspans, in the position they adopt in the slow speed portion.

FIG. 8 is a detail of FIG. 7, on a larger scale, at the transitionbetween two consecutive treadboards.

FIG. 9 shows a view in perspective of a series of treadboards with theadjacent chain spans, in the position they adopt in the high speedportion.

FIG. 10 is a detail of FIG. 9, on a larger scale and suppressing theside chains, at the transition between two consecutive treadboards.

FIG. 11 shows in perspective a series of treadboards and adjacent chainspans, in the position they adopt in the accelerating and retardingportions.

FIG. 12 is side view of a span of an auxiliary chain which engages withthe traction chains.

FIG. 13 is a side elevation in schematic form of the exit portion of theaccelerated walkway, showing a possible pulling or traction mechanism.

FIG. 14 is a side elevation in schematic form of the exit portion of theaccelerated walkway, showing a variant in the implementation of thetraction system.

FIG. 15 shows in perspective a series of treadboards and adjacent chainspans, with the pertinent guides, in the position they adopt in theaccelerating and retarding portions.

FIG. 16 shows a view in perspective a traction chain span, in accordancewith another possible configuration, in the maximum speed portion.

FIG. 17 shows a view in perspective a traction chain span, in accordancewith another possible configuration, in the maximum speed portion.

FIG. 18 shows a view in perspective in schematic form of the handrail ofthe accelerated walkway, in the maximum speed portion.

FIG. 19 shows a side view in schematic form of another possible solutionfor the handrail, making use of various conventional handrails atconstant speed.

In FIG. 1 is shown in schematic form, in a side view, an acceleratedwalkway which includes outermost portions for entrance (1) and exit (2),followed by slow speed portions, with reference number 3, inside whichruns and accelerating portion 4 and a retarding portion 5, next to theentrance and exit respectively, and between which runs an intermediate,high speed portion 6.

The movable surface 7 of the walkway is comprised of sets oftreadboards, each set formed by a front treadboard 8 and another reartreadboard 9, FIGS. 7 to 11, grooved and of different length, and thetreadboards are articulated to each other along an axis perpendicular tothe direction of movement.

The rear treadboard 9 of each set of treadboards is mounted on twolateral traction chains 10 and on side guidance elements 11 and 12, FIG.15.

The chains 10, as can be seen in FIGS. 4 to 6, are formed in the exampledescribed by elbowed links 13 and straight links 14 arranged inalternate positions with respect to each other. However the chain couldhave another formation, for example on a base of elbowed links only orinclude a greater number of straight links between consecutive elbowedlinks.

Each elbowed link 13 is articulated, through the end of one of itsstraight segments, with the adjacent links, be they straight or elbowed.

As can be appreciated from FIGS. 7 to 11, the rear treadboard 9 of eachset of treadboards, has on each of its sides longitudinal guides 15 andtwo rear coaxial rollers with reference number 16, which form part ofthe side chains 10. These rear treadboard also have on each of theirsides front coaxial rolling elements 17 which are run on lateral guides18, FIGS. 2, 3 and 15.

Returning to FIGS. 7 to 11, the front treadboard 8 of each set oftreadboards has on each of its sides sliding or rolling elements capableof moving over the lateral guides 15 of the rear treadboardcorresponding to the set of treadboards located immediately in front, ascan be clearly appreciated from FIGS. 9 and 10.

The elbowed links 13 rest on the side guides 11 and 12 through rollers21 and 22 having axle perpendicular to the link and situated at theoutermost points of the segments of elbowed links 13.

In FIGS. 2 and 3 it can be appreciated how the guide 11 assists in thechange of direction in the movement of the chain.

The rolling elements 21 and 22 of the elbowed links, by resting on theguides 11 and 12, produce the swivelling of the totality of the links,both elbowed and straight, between a position of being folded, whichcoincides with the end of the walkway 1, 2 and 3 and is shown in FIGS. 6and 7, in which the length of the chain is reduced and the partialoverlapping of the treadboards 8 and 9, and a position of maximumextension, which corresponds to the high speed portion 6 of the walkway,FIG. 1, and is shown in FIGS. 4, 5 and 9, in which the chain attains itsmaximum length, in order to produce the positioning of the treadboards 8and 9 in coplanar alignment.

The swivelling of the links takes place progressively in portions 4 and5, FIG. 1, originating a variation in speed of displacement on thesurface defined by the treadboards 8 and 9. FIGS. 11 and 15 show anintermediate position of the treadboards 7 within the accelerating orretarding portions.

As can be appreciated from FIG. 10, the two treadboards 8 and 9 of eachset have complementary adjacent edges, able to couple with each other inthe coplanar position of said treadboards.

As can be better seen in FIG. 5, the chains 10 also have rollers 25,coincident with the elbow of the elbowed links with which a chain 26engages, FIG. 2, which maintains the spacing of the different elementsin the slow speed portion, reducing the stress that has to be withstoodby chains 10 and so facilitating the turning of the treadboards betweenthe lower path and the working path. The chain 26 is constituted by twotypes of link 27 and 28, FIG. 12, of profile suitable for the diameterof the wheel 25 of the elbowed links with which it has to engage. Thisdrawing corresponds with a preferred embodiment, though equally possibleare other configurations in which this caterpillar chain 26 is notpresent.

In addition to the embodiment shown in FIG. 12, other differentembodiments are possible for the caterpillar chain 26, as a function ofthe pitch of the main chain, the speed ratio to be attained, and thediameter of the wheel to be engaged.

The chain 26 can engage in turn in two pinions not shown and the meshingbetween this chain 26 and the chains 10 is assured by means of someinternal guides on said chain 26. In the accelerating portion of thechains 10 the chain 25 no longer engages with them and the position ofthe links shall be determined by the guides 11 and 12.

In the centre part of the walkway, the treadboards 8 and 9 run atmaximum speed, and the chains 10 are in their most extended position, ascan be seen in FIG. 4. If necessary, additional units for powertransmission shall be included which are synchronised with the main unitwhich shall go in the exit portion. These units can consist ofcaterpillar type traction chains, similar to those described for theentrance and exit portion of the FIGS. 2 and 3, but having theirgeometry adapted to the position of the main chains in this portion.

The guides 11 and 12, in the entrance portion of FIG. 3, produce thegradual unfolding of the links, whilst in the exit portion of FIG. 2,they produce the gradual folding thereof.

As has already been indicated, the guides 11 and 12, together with guide18, serve to define the relative position of the links and for guidancein the change in direction of circulation of the chain and treadboards.

The chain 26 can produce the traction of the treadboard assembly througha motorised reduction-gear unit which transmits its power to said chain.

In FIGS. 13 and 14 other possible solutions are shown for producing thetraction of the main chains 10. In FIG. 14 treadboards 8 and 9 once thetransition has taken place with the fixed part of the walkway. The mainchains 10 mesh with toothed wheels 29 at maximum speed. In FIG. 13 thissystem is combined with the caterpillar type chain 26 system.

The chains 10 present in the minimum speed portion the minimum anglebetween the different links. FIG. 6 shows a detail in perspective of thechain folded into this position.

In the entrance and exit portions, treadboards 8 and 9 travel at lowspeed, for which reason the rectangular treadboards 9 are covered by thecomb-shaped treadboards 8, FIG. 7. The walking surface of thecomb-shaped treadboards 8 is flat and grooved to achieve a securetransition between the fixed entrance and exit treadboards and themoving treadboards of the walkway. In FIGS. 7 and 8 can be seen detailsof the treadboards in these slow speed portions. In particular, it ispossible to see the extremities of the grooved treadboards 8, whichengage in the extremities of the following treadboards. It is alsopossible to view the position of the supporting wheels 19 of thetreadboard 8 on the inside of the guides 15 of the treadboard 9 whichfollows, with the axle coincident with the intersection of two planesparallel to and equidistant from the respective walking surfaces of theadjacent preceding and ensuing treadboards. In FIG. 7 the transition isalso seen between the fixed part of the walkway 29 and the movingtreadboards with a system of combs similar to that to be found inconstant speed walkways.

In FIGS. 9 and 10 are shown details of the treadboards 8 and 9 in themaximum speed portion, together with the chains. The grooves at theextremities of the treadboards engage with the grooves at theextremities of the ensuing treadboard, practically eliminating the riskof accidents due to catching, trapping, pinching, etc.

FIG. 11 shows a detail of the treadboards in the portions of transitionbetween those of minimum speed and those of maximum speed, that is inthe portions of accelerating and retarding. In these portions themovements take place maintaining the comb-shaped treadboards 8horizontal, hence in both portions there is a slight increase in slope.

As already mentioned, the walkway shall also include a support structurefor all elements, side balustrades adapted to the form of the walkway,electrical and safety fittings suitable for the operation of the walkwayand side handrails with ancillary drive systems, which shall movepractically at the same speed as the neighbouring treadboards.

In the operation of the walkway, treadboards 8 and 9, after covering adistance at slow speed, in entrance portion 1, FIG. 1, start toaccelerate and therefore separate from each other. The gaps which areformed between the treadboards 8 are covered by treadboards 9. In thepreferred configuration, this movement occurs without varying the angleexisting between each set of treadboards 8 and 9, thus treadboards 8 canalways remain parallel to the horizontal plane and treadboards 9 at adetermined angle with respect to them. In this manner a slight change inlevel would be produced between the slow speed portion and the maximumspeed portion, shown with reference number 6 in FIG. 1. To achieve thismovement, the projection of the speed on the direction perpendicular tothe slotted surface of the treadboards 9 must remain constant. In thelast stage of the acceleration, treadboards 9 rotate about the pin whichjoins them to treadboards 8. In the acceleration portion 4, chains 10unfold until they are completely extended in the high speed portion 6,all of which can be appreciated in FIG. 3. In the acceleration portion,it is also possible to have a configuration in which there is novariation in slope. In that case, the angles between treadboards 8 and 9shall vary in order to ensure the covering of the gaps that would beproduced by the relative displacement of the treadboards.

Thanks to the position of the lateral rollers 19 which support thetreadboards 8 and to the position of the guides 15 of the treadboards 9,in the maximum speed portion all treadboards are located in the sameplane, and a completely smooth working surface is achieved. For this,the axle of the supporting rollers 19 must coincide with theintersection of two planes parallel to and equidistant from the walkingsurfaces of treadboards 8 and 9 and the guides 15 which come joined tothe treadboards 9 must be accelerated parallel to the slotting thereof.This characteristic is an important advantage of this walkway withrespect to other previous solutions.

When approaching the exit portion 2, FIG. 1, the treadboards enter aretarding portion 5 in which the opposite movement takes place to thatdescribed for the accelerating portion. In the preferred configurationtreadboards 8 and 9 again climb a small slope until the slow speed exitportion is reached. The position of the surfaces on which the user cantread is horizontal, on the treadboards 8, or sloping in the oppositedirection to the motion on treadboards 9, whereby the stability of theuser experiencing the deceleration is enhanced. This constitutes a majoradvance with respect to the state of the art. In the slow speed portion3, close to the exit, treadboards 8 and 9 are moved horizontally at slowspeed. The user only sees the comb-shaped treadboards 8, the rectangulartreadboards 9 being hidden below them. In this portion the chainrecovers its fully folded condition, as can be appreciated in FIGS. 2,13 and 14.

In the configuration of the walkway of the invention, the transitionbetween the moving treadboards and the fixed portion for entrance andexit is done with a comb system similar to that employed in constantspeed walkways, as shown in FIG. 7.

The insertion of the elbowed links in the traction chains means that thefolding forces are small. These elbowed links have rolling elementspositioned at two points such that the forces applied by the guides 11and 12 upon them produce a turning couple in the link. In this mannerthe forces necessary for folding the chain are reduced, with respect toother solutions known, which signifies a major advantage from the pointof view of performance of the installation and of the maximum reductionin speed that can be achieved with the mechanism.

As well as the caterpillar type chain drive systems, other solutions canbe employed, such as traditional high-speed traction systems or a mix ofboth systems. In these solutions, the treadboards would accelerate afterpassing the transition with the fixed part of the walkway.

FIG. 16 shows a solution in which the two treadboard side chains arejoined by rods 30. In this embodiment, as that shown in FIGS. 4, 5 and9, in the position of maximum chain extension, the straight links 14 arepositioned in alignment with the adjacent section of the elbowed links13.

FIG. 17 shows a solution similar to that of FIG. 16, in which the linksare of different length. In this case, in the position of maximum chainextension, the straight links 14 are not aligned with the adjacentsection of elbowed links 13.

FIG. 18 shows a possible embodiment of a variable speed handrail,constituted by means of a succession of blocks or sections 31 of anelastomeric foam separated by platelets 32. These platelets 32 carryguides 33 on the underside, which determine a transversal groove 34,through which they are in relation with a pantograph 35, the outermostarticulations 36 of which are housed in the slots 34 of the guides 33.Pantograph 35 is joined by means of the pillars 36 to a chain similar tothat described for the movement of the treadboards, formed by elbowedlinks 13′ and straight links 14′ which incorporate rollers 21′ and 22′which rest on guides in order to produce the folding and unfolding ofthe chains, as described above.

Each certain distance the blocks 31 of the handrail rest on someindependent idlers 37 which serve as guiding elements for said handrail.

The platelets 32 prevent the deforming of the handrail outside itsplane.

With the constitution described, the handrail suffers compression in theslow speed sections of the walkway and is elongated in the maximum speedsections, due to the chain made of links 13′ and 14′, in like manner tothat described for the treadboards of the walkway.

A handrail such as that described would maintain its maximum length inthe portion of maximum speed, and it would be compressed in theretarding portion. In the slow speed portions of entrance and exit, thehandrail would be compressed. In the accelerating portion, the handrailwould again be extended to its maximum length.

In FIG. 19, similar to that of FIG. 1, the solution that is shown isthat of employing various continuous, endless handrails running atconstant speed. The acceleration is produced by the difference in speedsof the different handrails. This solution, already known, can belikewise applied in this walkway. The number of handrails necessarydepends on the difference reached in speeds of the slow portion and thefast portion.

In a variant of this solution, the handrails 38 of FIG. 19, can be ofvariable speed, as illustrated in FIG. 18. In that case, the handrail ofthe high speed portion 39 would the closed endless type, similar to thepresent constant, speed handrails.

What is claimed is:
 1. An accelerated walkway, designed for conveyingpassengers or goods in a direction of movement, made up of sets oftreadboards of variable length which are mounted between lateraltraction chains, a drive mechanism being related with said lateraltraction chains, each set of treadboards comprises a front treadboardand a rear treadboard, said front treadboard and said rear treadboardbeing grooved and mutually articulated along an axis perpendicular tothe direction of movement; the rear treadboard of each set oftreadboards is mounted on said lateral traction chains and on lateralguidance rails; the front treadboard of each set of treadboards rests onand is displaceable over the rear treadboard of a next set oftreadboards in the direction of movement by means of guide elements;each of the lateral traction chains includes rigid elbowed links andstraight links consecutively articulated to each other through theirextremities and are run between lateral guides that cause said links toswivel between a folded position, in which the length of the chain isreduced, resulting in the partial overlaying of the treadboards, and amaximum extension position, resulting in the positioning of thetreadboards in coplanar alignment.
 2. The accelerated walkway inaccordance with claim 1, wherein the swivelling of the links takes placein a progressive manner between a centre span of the lateral tractionchains and outermost spans thereof, whereby a variation in speed isachieved of the displacement on the surface defined by the treadboards,said speed being maximum in the centre span and minimum in the outermostspans, between which an acceleration and retardation occurs incorrespondence with an entrance portion and an exit portion of thechain, respectively.
 3. The accelerated walkway in accordance with claim1, wherein the lateral traction chains are comprised of elbowed linksand straight links, each elbowed link having two straight segments, oneof the straight segments of the elbowed links being articulated throughits extremities with adjacent links, said adjacent links being straightor elbowed.
 4. The accelerated walkway in accordance with claim 1,wherein the rear treadboard of each set of treadboards is fitted on eachof its sides with longitudinal guides, with two rear coaxial rollersthat form part of the lateral traction chains, and with front coaxialrollers which can move over the side guidance elements, and wherein thefront treadboard of each set of treadboards has on each of the sidesfront coaxial sliding or rolling elements, which can move over thelongitudinal guides of the rear treadboard corresponding to thefollowing set of treadboards in the direction of movement.
 5. Theaccelerated walkway in accordance with claim 1, wherein the elbowedlinks rest on the lateral guide rails through two rolling elements withaxles perpendicular to the link.
 6. The accelerated walkway inaccordance with claim 1, wherein the front and rear treadboards of eachset of treadboards have complementary adjacent edges which can becoupled to each other in the coplanar position of said treadboards. 7.The accelerated walkway in accordance with claim 1, wherein, in thecentre portion, in which the lateral traction chains run in the maximumextension position, the treadboards of the different sets occupycoplanar positions, whilst in the outermost portions, in which thelateral traction chains run in the position of maximum folding, the reartreadboards of the different sets run under the front treadboards, thesefront treadboards being in a horizontal position, with the adjacentedges coupled to each other, coinciding in any position the axle of therolling or sliding elements of these front treadboards with the line ofintersection of the parallel planes equidistant from the respectivewalking surfaces of the front sub-treadboard and the adjacent rear one.8. The accelerated walkway in accordance with claim 7, wherein, intransition spans, between portions of maximum extension and portions ofmaximum folding, the overlapping between front and rear treadboardsvaries progressively, the front treadboards being maintained in anoticeably horizontal position and the rear treadboards at a slightinclination, in opposition to the direction of movement.
 9. Theaccelerated walkway in accordance with claim 1, wherein the tractionchains engage at their outermost points with auxiliary pinions or chainsthat maintain the distance between the links and also facilitate thetilting of the treadboards between the forward-going and backward-goingsegment of the assembly.
 10. The accelerated walkway in accordance withclaim 9, wherein at least one of the auxiliary pinions or chains is inrelation with the drive mechanism.
 11. The accelerated walkway inaccordance with claim 1, wherein, in the entrance and exit portions, thefront treadboards of the sets of treadboards are moved in a coplanar andaligned manner, performing the transition with the fixed surface of thewalkway by means of a system of combs.